—Mark A. Bedau, 1997
"The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe.The constructionist hypothesis breaks down when confronted with the twin difficulties of scale and complexity. At each level of complexity entirely new properties appear. Psychology is not applied biology, nor is biology applied chemistry. We can now see that the whole becomes not merely more, but very different from the sum of its parts."
—P.W. Anderson, 1972